From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88CD0C433F5 for ; Sat, 7 May 2022 10:02:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1446210AbiEGKFA convert rfc822-to-8bit (ORCPT ); Sat, 7 May 2022 06:05:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232437AbiEGKE4 (ORCPT ); Sat, 7 May 2022 06:04:56 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id AFD8D3AA67 for ; Sat, 7 May 2022 03:01:07 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-285-a07I9tQYN4-ed0PF2CZy2w-1; Sat, 07 May 2022 11:01:04 +0100 X-MC-Unique: a07I9tQYN4-ed0PF2CZy2w-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Sat, 7 May 2022 11:01:03 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.033; Sat, 7 May 2022 11:01:03 +0100 From: David Laight To: 'Jagdish Gediya' CC: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "gregkh@linuxfoundation.org" , "rafael@kernel.org" , "akpm@linux-foundation.org" , "keescook@chromium.org" , "andriy.shevchenko@linux.intel.com" , "geert@linux-m68k.org" , "linux@roeck-us.net" , "adobriyan@gmail.com" Subject: RE: [PATCH] kobject: Refactor kobject_set_name_vargs() Thread-Topic: [PATCH] kobject: Refactor kobject_set_name_vargs() Thread-Index: AQHYYU3qLELCyca9fE2SaEK1v39Vvq0R6/5wgAAc1ACAASXE8A== Date: Sat, 7 May 2022 10:01:03 +0000 Message-ID: <97b8979ff52c4404bf74eeda574d6b23@AcuMS.aculab.com> References: <20220506133309.36794-1-jvgediya@linux.ibm.com> <5902e26ef400451b966be2dd0fbd1575@AcuMS.aculab.com> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jagdish Gediya > Sent: 06 May 2022 18:24 ... > > Are you sure this can ever work from a module? > > This all relies on: > > > > static inline bool is_kernel_rodata(unsigned long addr) > > { > > return addr >= (unsigned long)__start_rodata && > > addr < (unsigned long)__end_rodata; > > } > > > > which isn't going to do anything sane given an "xxx" inside a module. > > > > Indeed can kobject_set_name_vargs() end up with a constant string > > inside a module? > > No, kobject_set_name_vargs() is not exported. I exported > set_name_vargs() because it can have a broader use, but you are right > it shouldn't be exported. I was thinking that some function that creates a 'kobject' could easily be called from a module - so you end up calling the set_name code from a module and then end up calling kfree() on a literal from a module. Now it might be that it is impossible to actually the quoted literal from a module into somewhere that is_kernel_rodata() is applied to. But, as i said, it is fragile. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)